The ML example was missing the second half of the ML niceness - efficient pattern matching at syntax levels which makes for a really nice and understandable code, especially when writing complex compound clauses.
"...could probably use templates or macros to autogenerate.."
... which kind of highlights that ML example even more. In Ocaml or F# that original definition would have been more or less enough to start writing nice, efficient parsing code.
The sum types are not the only thing, IMO, that ML-family has going for it. As for example F# contains pairs and lists as syntax level constructs (rather than library add-ons) lot of code can be written at a really high level before optimization - in the same language - if it's needed.
"...could probably use templates or macros to autogenerate.."
... which kind of highlights that ML example even more. In Ocaml or F# that original definition would have been more or less enough to start writing nice, efficient parsing code.
The sum types are not the only thing, IMO, that ML-family has going for it. As for example F# contains pairs and lists as syntax level constructs (rather than library add-ons) lot of code can be written at a really high level before optimization - in the same language - if it's needed.